Umm, more information please. How did our friendly Yemeni a) travel to America (on what type of visa) and b) why was the state of California nice enough to issue him an identification card? San Francisco Chronicle:

A Vallejo man holding a Yemeni passport tried to break into the locked cockpit of an American Airlines flight bound for San Francisco before crew members and passengers, including two retired law enforcement officers, were able to subdue him, authorities said Monday.
Rageh Ahmed Mohammed Al-Murisi, 28, who was carrying a California identification card in addition to his Yemeni passport, was wrestled to the floor of the Boeing 737 near the end of the four-hour flight Sunday night. He was charged in U.S. District Court in San Francisco with interfering with a flight crew and is scheduled to appear in court today with an Arabic interpreter.
Al-Murisi, 28, suffered minor injuries as a result of being tackled, but no one else was injured, and flight safety was not compromised, authorities said.
San Francisco airport police Sgt. Michael Rodriguez said it’s not clear what Al-Murisi had in mind and that the suspect had no known ties to terrorism.
The incident began about 8:50 p.m. when American Airlines Flight 1561, carrying 156 passengers and six crew members from O’Hare International Airport in Chicago, was about a half hour from landing at San Francisco International Airport, authorities said.

The rest here.